FIGURE 2.

Arsenic trioxide decreases the stability of ΔNp63α protein but has little effect on the level of ΔNp63 transcript. A, the half-life of ΔNp63α protein was shortened by arsenic trioxide in ME-180 cells. Western blot analyses were prepared with extracts from ME-180 cells that were treated with cycloheximide (50 μg/ml) (CHX) in the absence or presence of 10 μm arsenic trioxide for 0–8 h and then probed with antibodies against ΔNp63 and actin, respectively. B, the relative levels of ΔNp63 protein measured in A were normalized by levels of actin protein and then plotted versus time. C–E, the level of ΔNp63 transcript is not obviously altered by arsenic trioxide. RT-PCR analysis was performed with total RNAs isolated from ME-180 (C), HaCaT (D), and MCF10A (E) cells untreated or treated with 10 μm arsenic trioxide for 6 or 9 h. Actin mRNA was amplified as a loading control.